A general voice recognition system performs a search process of expressing a target domain to be recognized as one search space and searching a word string which is most similar to an input voice signal (voice data) under a condition of the corresponding search space. That is, the general voice recognition system provides a voice recognition service having the same single search space to all voice recognition service users.
When a universal single search space is integratedly provided as described above, it is difficult to provide a customized service suitable for a situation of a user and voice recognition accuracy is lowered under a specific situation.